Preparation of TiO2/α-Fe2O3@SiO2 Nanorod Heterostructures and Their Applications for Efficient Photodegradation of Methylene Blue

A facile solvo-hydrothermal method was used to synthesize sub-100 nm diameter TiO2/α-Fe2O3@SiO2 nanorods (TiO2/HNRs@SiO2). Thermal annealing of TiO2/HNRs@SiO2 activated the photosensitizing crystalline TiO2 domains containing mixed anatase and rutile phases. The photocatalytic degradation of methylene blue (MB), conducted using thermally annealed TiO2/HNRs@SiO2 photocatalysts, was successfully demonstrated with ~95% MB removal efficiency under mild conditions of pH = ~7 and room temperature using ~150 min of solar irradiation. The enhanced removal efficiency was attributed to the rapid adsorption of MB onto the TiO2/HNRs@SiO2 surface via favorable electrostatic interactions and the synergistic integration of α-Fe2O3 and TiO2 into nanorod heterostructures with bandgaps of 1.99–2.03 eV, allowing them to absorb visible light for efficient photocatalytic decomposition. This study provides insights into designing photocatalysts with improved selectivity for sustainable water treatment and environmental remediation.